It has been reported that in the more aggressive subtypes of breast cancer, such as basal-like and TNBC, global levels of H3 lysine 27 trimethylation (H3k27me) are reduced compared to less aggressive subtypes, like luminal A and HER2-enriched, suggesting that higher H3K27me levels could be linked to a better prognosis [191,193,194]. The gene discussed is ERBB2; the disease is breast carcinoma.